1. Field of the Invention
The present invention relates to a switch device for use in a timepiece such as a wristwatch.
2. Description of the Related Art
For example, a wristwatch is known which includes a switch device having an operation member such as a crown provided on the wristwatch case so as to be able to be pulled out, as described in Japanese Patent Application Laid-Open (Kokai) Publication No. 2006-194834.
This type of switch device is structured such that the operation member projecting outwardly from the wristwatch case is pulled out and the operation member is rotated in this state, whereby the time is corrected.
In the structure of this switch device, a winding-stem pipe is attached to a through hole of the wristwatch case, a shaft section of the operation member is inserted into the winding-stem pipe, an outer end of the winding stem is attached to the shaft section of the operation member and an operation head section projecting outwardly from the wristwatch case is provided at the outer end of the shaft section.
This switch device also includes a lock section which locks the operation member in a pushed state when the time is not corrected. The lock section includes a ring member having a plurality of engaging projections attached to the operation head section and a plurality of engaging groove sections provided on the outer perimeter of the winding-stem pipe projecting outwardly from the wristwatch case to engageably lock the engaging projections of the ring member.
In this switch device, when the operation member is rotated, the engaging projections of the ring member rotate to release locks of the engaging projections with respect to the plurality of engaging groove sections. In this state, the operation member is pulled out for rotating operation, and thereby the time can be corrected. Also, when the operation member is pushed in to be rotated, the engaging projections of the ring member rotate to be engaged with the plurality of engaging groove sections, whereby the operation member is locked in a pushed state.
However, there is a problem in this type of switch device in that, in both of the cases where the operation member is pushed in and locked and where the lock is released and the operation member is pulled out, when the operation head section of the operation member receives an external impact the impact is directly exerted onto the operation member and the winding-stem pipe, whereby the operation member and the winding-stem pipe are damaged, and the sealing performance of the winding-stem pipe with respect to the wristwatch case is decreased.